As representatives of six nations prepare in Beijing to discuss North Korea's nuclear-weapons program, China says it will oppose sanctions against the North.

The warning against sanctions came from China's deputy foreign minister, Wang Yi, who spoke to Chinese state-run media as delegates in Beijing prepared to begin the delicate, three-day talks.

Mr. Wang said China does not approve of sanctions or pressure, and it would not support war.

The talks among China, Japan, North and South Korea, Russia and the United States will center on U.S. demands for North Korea to dismantle its nuclear weapons program in a verifiable manner.

North Korea is demanding that the United States agree to a non-aggression pact. Pyongyang has repeatedly accused Washington of preparing to invade North Korea - much, North Korean leaders say, as it did Iraq earlier this year.

Earlier, Chinese Vice President Zeng Qinghong called for North Korea's concerns over its security to be addressed in the upcoming discussions.

The Bush administration has said that if North Korea abandons the weapons program, Washington will find some diplomatic language to allay the North's security concerns.

Diplomats taking part in the talks continued to play down expectations of immediate or major results.

A Russian official said perhaps the biggest challenge would be to keep all sides at the table through what promises to be a long and complicated process. The North Koreans, he said, have a record of being slow and difficult negotiators.

Another official said the meeting could be considered successful if all sides simply agreed to a second round of talks.

In his remarks Deputy Foreign Minister Wang, who heads the Chinese delegation, also cautioned against expecting too much. Mr. Wang said that with six countries sitting together, it is clear that the world community is actively interested. He said the issue is very complicated, and all problems will not be resolved in just one or two meetings.

The head of the U.S. delegation, Assistant Secretary of State James Kelly, characterized the talks in upbeat terms upon his arrival Monday. He praised China's role in arranging the meeting, and said all sides would have a chance to present their views.

"I am very happy to be back in Beijing," said Mr. Kelly. "We have worked for a long time. The Chinese have worked for a long time to have these multilateral talks. We will be getting going Wednesday morning and we are looking forward to a direct and fair exchange of views."

The talks are an effort to end a crisis that erupted in October, when North Korea admitted to a delegation headed by Mr. Kelly that it had restarted its nuclear weapons program, in violation of international agreements.